High energy mixing device

ABSTRACT

This disclosure is directed to a pumping and mixing device through which fluids are circulated. The device comprises a tank with a mixing head which contains high energy mass exchange impinging nozzles and a jet pump through which fluids from the mixing head pass under the driving force of at least one centrifugal pump. With the centrifugal pump inlet pressure increased by the use of the jet pump, large quantities of gases (or less dense fluids) may be injected at a point between the jet pump and the centrifugal pump inlet while still having the centrifugal pump produce a high discharge head (i.e., no cavitation). The fluid from the centrifugal pump outlet may be divided into two streams. One stream is passed through nozzle devices into the tank and the other is passed back through the jet pump. The device and its method of operation may be illustrated by the process of clarifying aqueous solutions of sugar and dissolving sugar crystals in water.

United States Patent 1 Hege [ Oct. 2, 1973 l l HIGH ENERGY MIXING DEVICE Douglas W. Hege, Woodland Hills, Calif.

[73] Assignee: Hege Advanced Systems Corporation, Woodland Hills, Calif.

[22] Filed: Jan. 5, 1972 I21] Appl. No.: 215,460

[75] Inventor:

Primary Examiner-Wayne A. Morse, Jr. Assistant Examiner Philip R. Coe Altorney-Hugh A. Chapin et a1.

[57] ABSTRACT This disclosure is directed to a pumping and mixing device through which fluids are circulated. The device comprises a tank with a mixing head which contains high energy mass exchange impinging nozzles and a jet pump through which fluids from the mixing head pass under the driving force of at least one centrifugal pump. With the centrifugal pump inlet pressure increased by the use of the jet pumip, large quantities of gases (or less dense fluids) may be injected at a point between the jet pump and the centrifugal pump inlet while still having the centrifugal pump produce a high discharge head (i.e., no cavitation). The fluid from the centrifugal pump outlet may be divided into two streams. One stream is passed through nozzle devices into the tank and the other is passed back through the jet pump. The device and its method of operation may be illustrated by the process of clarifying aqueous solutions of sugar and dissolving sugar crystals in water.

13 Claims, 7 Drawing Figures PATENTEDHBT 2 m 3.762.689

SHEET 1 [IF 4 I CE] a WWWM 4 HIGH ENERGY MIXING DEVICE THE INVENTION This invention is directed to a method and device for the high energy mixing of fluids. The nature of the fluids can vary widely and may comprise one or more liquids with a gas and/or a solid which may be soluble in the liquid. The device comprises a mixing chamber into which the fluids are pumped. The fluid passes through a jet pump at the bottom of the mixing chamber which is connected to one or more centrifugal pumps which recirculate the fluids back to the mixing chamber. Air, other gases or lighter fluids may be injected into the fluid at a location between the jet pump outlet and the centrifugal pump inlet. The centrifugal pump outlet discharges the fluid through nozzles which are designed to form streams which impinge upon each other for mass transfer to increase the mixing efficiency of the process. A portion of the fluid from the pump outlet may be diverted back into the jet pump.

The process and device are illustrated in greater detail by the accompanying figures.

FIG. 1 is an overall view of the mixing and pumping apparatus.

FIG. 2 is a detailed view of the jet pump.

FIG. 3 shows the configuration of the recirculating system below the mixing tank.

FIG. 4 is a detailed view of a mixing nozzle.

FIG. 5 illustrates the flow of fluids from the mixing nozzles.

FIG. 6 is a view in perspective of the base of the dispersant port of FIG. 4.

FIG. 7 is an alternative embodiment of the recirculating nozzle system.

Mixing tank 10 has an inlet pipe 11 and outlet pipe 12. Liquid passes from the inlet pipe into the mixing tank and then into a jet pump, identified generally by the reference numeral 13.

The jet pump is shown in greater detail in FIG. 2. The liquid in the mixing tank passes through a reduced cross-sectional area formed by a ribbed section 14, a venturi, in the jet pump, which increases the speed and turbulence of the liquid. The liquid then enters chamber 15 which contains air-ejector outlets l6, 16 (FIG. 1). A compressed air tank 17 delivers air through regulators l8 and 19, 19', each of conventional design, into the ejectors which are directed away from the direction of the incoming liquid. An air pressure of from about 15-90 psig may be used, a lower range of 2030 psig is satisfactory for most pruposes. The air-liquid mixture is pulled from chamber 15 by the turbine members 20,

20', which are driven by motors 2I, 21' respectively. The air pressure from the ejectors assists in forwarding the liquid and preventing cavitation. The air-liquid mixture passes from chambers 22, 22' into return conduits 23, 23 and then into return chamber 24. The return chamber 24 is within, and is formed by, the inner wall 25 and outer wall 26 ofjet pump 13, FIG. 2. The return chamber has two types of exit ports, the dispersant ports 27 and the return ports 28. A dispersant port is shown in detail in FIGS. 4 and 6 and the configuration of four dispersant ports in the circumference of wall 26 of jet pump 13 are shown in FIG. 5. The dispersant ports comprise a generally concave member 29 having holes 30, 30'. The streams emerging from the holes converge and impinge upon each other as shown by the arrows in FIG. 4. These streams constitute a primary mixing and momentum exchange with the system illustrated. The concave member 29 may terminate at wall 26 or, as shown, extend therefrom by collar member 31. The flow patterns from the streams emerging from 29 are indicated generally by arrows 32. The overall flow pattern from the dispersant ports is illustrated by the arrows 33 in FIG. 5. This constitutes a secondary mixing and vortex generation. the currents generated rise in the tank as illustrated by arrows 33'. The return ports are connected to return conduits 34, 34' which discharge into the jet pump 13, FIG. 2.

The above described unit may be constructed in a wide variety of sizes from small units of about ten gallons capacity to large units of over 500 gallons. Representative sizes and operation will be illustrated for a unit of 500 gallons batch-capacity with a high throughput. For such a unit the tank 10, of stainless steel, is about 4 feet in diameter and 6 feet high. The liquid enters the jet pump 13 having an opening at the top and bottom of about 5 inches and a venturi 14 width of about 2%inches. The air ejectors 16, 16' discharge air at about 20-30 psig. The liquid movement is directed by two Tri-Flow No. 328F pumps which have a capacity of about 500 gallons per minute. The pumps, illustrated by turbines 20,20 in chambers 22, 22', have inlets from chamber 15 for the air-liquid mixture of 4 inches and outlets for return conduits 23, 23' of 2 inches. The motors 21, 21' which drive the pumps have a horsepower rating of 75. The return conduits 34, 34' are about 1 inch in diameter and the liquid exits back into the jet pump from the 9% inch nozzle ends of these return conduits. The dispersant ports each have an opening of about 55 inch at the outer periphery of wall 26. The dispersant holes have a diameter of about a inch.

The system of this invention employs the three fundamental mixing processes of mass transfer, eddy diffusion and molecular diffusion. The mass transfer mixing occurs largely in the high energy, high volume transfer of material which recirculates from the jet pump 13, through the centrifugal pump system 22-23, and back through return conduits 34. This will be referred to as flow path I. The eddy diffusion and. molecular diffusion predominate in the liquid bulk in the tank. The liquid in the tank undergoes constant movement due to the rising eddies 33'. Liquid in the tank also flows downward with incoming liquid from inlet 11 and a portion flows outward and is caught in the eddy currents. This will be referred to as flow path II. The ratio between'the flow of liquid in paths I and II is controlled by adjusting the openings of the dispersant 27 and return 28 ports. The control means may be at one vor both of the types of dispersant ports or a control means may be attached at the nozzle ends of return conduits 34. Such a control means is shown in FIG. 7 which illustrates a head member 35 in which the return conduits 34 terminate. The control means of head 35 may be of conventional design, such as adjacent rotatable perforated plates, in which the perforations can be adjusted into or out of alignment.

Two or more high energy streams of heterogenous mixtures of masses impinging on each other give a mass exchange such that the more dense substances exchange their position with the less dense substances and they then are in contact with fresh less dense material; thus enhancing mixing, dissolution, adsorption, and/or reaction. This exchange occurs primarily in three areas: (1) between the several streams which emerge from the nozzle 27 and impinge upon each other; (2) between these streams and the bulk of the fluid in the tank; and (3) between the fluid streams from conduits 34 and the fluid from the tank drawn into the jet pump.

With the centrifugal pump inlt pressure increased by the use of the jet pump, large quantities of gases (or less dense fluids) may be injected at a point between the jet pump and the centrifugal pump inlet and still have the centrifugal pump produce a high discharge head (i.e., no cavitation). The injection of this large quantity of gases (or less dense fluids) in the jet pump discharge where the pressure is as much as 35/40 psi above tank pressure or at least psi above the head tank pressure and where the gases/fluids are then subjected to an increasing pressure gradient (i.e., 60-200 psi) and a high turbulence in the pump, enhances gas/fluid diffusion as very small bubbles and its mixing, suspension, or absorption.

The method and apparatus of this invention is useful for the clarification of sugar. A sugar syrup to which phosphoric acid and lime were added was mixed in the device shown in FIG. 1 under the following conditions:

Clarifler 500 gal 250 gal 540 gpm 290 gpm 250 gpm 80 gpm 190 psig 21 psig Press-Throat NPSH HP Horsepower/motor Amps Recirculation Factor Air Flow Rate Pressure air Nozzles Pair of 0.332 0.472 dia 2.32 in 9 inches Tank Nozzles (4) Jet Nozzles (4/1) Jet Pump Throat Impeller Dia.

The resultant syrup contained from 50 to 100 ppm contaminants (average about 75 ppm) and 9,340 bubbles/cm. A comparable mixing procedure without the use of the jet pump gave a syrup having from 50 to 500 ppm contaminants (average about 150 ppm) and 2,577 bubbles/em The use of the jet pump therefore gave a better and more uniform product.

This invention may be used for the mixing or stirring of a wide variety of substances such as homogenization, dispersion, and reaction. The substances may be one or more liquids, which can be miscible or immiscible with each other, and may contain solids or gases which are soluble or insoluble therein. A particularly useful embodiment of the present invention is the aeration of liquids, such as industrial and municipal waste streams. The efficient aeration of such streams by the present invention reduces the pollution effects of the streams. A further embodiment is to mix other reactive gases, such as sulphur dioxide or chlorine, to effect sulphonation or chlorination of, for example, hydrocarbon streams.

This invention has been described in terms of specific embodiments set forth in detail. Alternative embodiments will be apparent to those skilled in the art in view of this disclosure, and accordingly such modifications are to be contemplated within the spirit of the invention as disclosed and claimed herein.

I claim:

1. A system for mixing a fluid which comprises a tank to hold said fluid; a jet pump, comprising a jet ejector conduit, and a venturi section, the inlet of said venturi section adapted to communicate with the fluid in said tank; a pump; means (A) to interconnect the outlet of the venturi section with the inlet of said pump, said means (A) adapted to increase the inlet pressure of said pump; means (B) to interconnect the outlet of said pump with the inlet of said jet ejector, and means (C) to interconnect the outlet of said pump with the fluid in said tank.

2. A method of mixing a material in a container which comprises passing the material through a pump means;

dividing said material from the pump into two streams; passing the first of said streams through dispersant ports in the form of self impinging streams;

passing the second of said streams through the inlet ofa jet pump which draws with it material from the container and provides the input for said pump means, and maintaining said first and second streams to induce a circulating stream of the material in said container.

3. The method of claim 2 wherein an additional fluid is injected into said pump means to increase the pressure at least 15 psi at the inlet of said pump means.

4. The method of claim 3 wherein said fluid is air.

5. The method of claim 2 wherein said material is an aqueous solution.

6. A method of treating in a container a stream containing a fluid and a second substrate which comprises passing said stream into a jet pump, wherein the inlet of said jet pump communicates with the interior of said container, passing the output of said jet pump through a conduit into a centrifugal pump, to increase the pressure at the inlet of said pump, passing the output of said centrifugal pump into said container from which fluid passes to the inlet of said jet pump and injecting an additional fluid into the output stream of said jet pump to increase pressure at the inlet of said centrifugal pump.

7. A system for mixing a fluid which comprises a tank to hold said fluid; a jet pump, comprising a jet ejector conduit and a venturi section, the inlet of said venturi section adapted to communicate with the fluid in said tank; a pump; means (A) to interconnect the outlet of the venturi section with the inlet of said pump; means (B) to interconnect the outlet of said pump with the inlet of said jet ejector, and means (C) to interconnect the outlet of said pump with the fluid in said tank, said means (C) comprising dispersant port members, each dispersant port comprising a plate member with holes therein adapted to pass fluid from the pump into the tank in the form of converging streams.

8. The system of claim 7 comprising a chamber positioned about said jet pump, the inlet of said chamber connected to said pump, and the outlets of said chamber being means (B) and means (C).

9. A system for mixing a fluid which comprises a tank to hold said fluid; a jet pump, comprising a jet ejector conduit and a venturi section, the inlet of said venturi section adapted to communicate with the fluid in said tank; a pump; means (A) to interconnect the outlet of the venturi section with the inlet of said pump; means (B) to interconnect the outlet of said pump with the inlet of said jet ejector; means (C) to interconnect the outlet of said pump with the fluid in said tank, and causing said stream to be divided into "168115 to eject air into Said P p Positioned irl Said a first part which is directed into said first predetermeans mined path and 10. The system of claim 9 wherein said means (D) comprises ejector conduits having outlets positioned 5 toward the Inlet. of sand pump and mlets connected to causing the streams of said first and second part to a compressed air system.

11. A method of treating a stream containing a fluid mm mm Sald stream m Said r and a second substance in a container which comprises The method of 31mm 11 wherem fluld mlected directing said stream from said container to flow into Said first predetermined P alon a fir t redetermined th under hi h- 13. The method of claim 12 wherein said fluid is air. mixing conditions through a pump a second part which is further divided into multiple streams which impinge upon each other and I j" UNITED STATES PATENT OFFI-CE CERTIFICATE OF CORRECTION Patent No. 3 7 62 689 Dated October '2, 1973 Inventor(s) Douglas w. Hege. Woodland Hills, California It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line-.50, "pruposes" should be --purposes--.

Column 3, line '7, "inlt" should be --inlet--.

Column r, line- 33, "substrate" should be --substance-.

Signedand sealed this 2nd dayof July 1974,

(SEAL).

Attest: I

EDWARD M. FLETCHER, JR. c. MARSHALL DANN Attesting Officer Commissioner of Patents FORM Po-wso (10-69) USCOMWDC I U.S. GOVERNMENT PRINTING OFFICE Ill 0*!5331, 

1. A gsystem for mixing a fluid which comprises a tank to hold said fluid; a jet pump, comprising a jet ejector conduit, and a venturi section, the inlet of said venturi section adapted to communicate with the fluid in said tank; a pump; means (A) to interconnect the outlet of the venturi section with the inlet of said pump, said means (A) adapted to increase the inlet pressure of said pump; means (B) to interconnect the outlet of said pump with the inlet of said jet ejector, and means (C) to interconnect the outlet of said pump with the fluid in said tank.
 2. A method of mixing a material in a container which comprises passing the material through a pump means; dividing said material from the pump into two streams; passing the first of said streams through dispersant ports in the form of self impinging streams; passing the second of said streams through the inlet of a jet pump which draws with it material from the container and provides the input for said pump means, and maintaining said first and second streams to induce a circulating stream of the material in said container.
 3. The method of claim 2 wherein an additional fluid is injected into said pump means to increase the pressure at least 15 psi at the inlet of said pump means.
 4. The method of claim 3 wherein said fluid is air.
 5. The method of claim 2 wherein said material is an aqueous solution.
 6. A method of treating in a container a stream containing a fluid and a second substrate which comprises passing said stream into a jet pump, wherein the inlet of said jet pump communicates with the interior of said container, passing the output of said jet pump through a conduit into a centrifugal pump, to increase the pressure at the inlet of said pump, passing the output of said centrifugal pump into said container from which fluid passes to the inlet of said jet pump and injecting an additional fluid into the output stream of said jet pump to increase pressure at the inlet of said centrifugal pump.
 7. A system for mixing a fluid which comprises a tank to hold said fluid; a jet pump, comprising a jet ejector conduit and a venturi section, the inlet of said venturi section adapted to communicate with the fluid in said tank; a pump; means (A) to interconnect the outlet of the venturi section with the inlet of said pump; means (B) to interconnect the outlet of said pump with the inlet of said jet ejector, and means (C) to interconnect the outlet of said pump with the fluid in said tank, said means (C) comprising dispersant port members, each dispersant port comprising a plate member with holes therein adapted to pass fluid from the pump into the tank in the form of converging streams.
 8. The system of claim 7 comprising a chamber positioned about said jet pump, the inlet of said chamber connected to said pump, and the outlets of said chamber being means (B) and means (C).
 9. A system for mixing a fluid which comprises a tank to hold said fluid; a jet pump, comprising a jet ejector conduit and a venturi section, the inlet of said venturi section adapted to communicate with the fluid in said tank; a pump; means (A) to interconnect the outlet of the venturi section with the inlet of said pump; means (B) to interconnect the outlet of said pump with the inlet of said jet ejector; means (C) to interconnect the outlet of said pump with the fluid in said tank, and means (D) to eject air into said pump positioned in said means (A).
 10. The system of claim 9 wherein said means (D) comprises ejector conduits having outlets positioned toward the inlet of said pump and inlets connected to a compressed air system.
 11. A method of treating a stream containing a fluid and a second substance in a container which comprises directing said stream from said container to flow along a first predetermined path under high-energy mixing conditions through a pump causing said stream to be divided into a first part which is directed into said first predetermined path and a second part which is further divided into multiple streams which impinge upon each other and causing the streams of said first and second part to mix with said stream in said container.
 12. The method of claim 11 wherein fluid is injected into said first predetermined path.
 13. The method of claim 12 wherein said fluid is air. 